Preparation of 4-alkanoylaryl benzyl ethers

ABSTRACT

A process for preparing 4-alkanoylaryl benzyl ethers of the general formula I ##STR1## where R is hydrogen, halogen, cyano; alkyl, alkoxy; 
     X is CH 2 , CH--CH 3 , CH--CH 2  --CH 3 , CH--OCH 3  or N--OCH 3  ; 
     Y is oxygen, sulfur, direct linkage or nitrogen; 
     m is 0, 1, 2 or 3; 
     R 1  is hydrogen; alkyl, alkenyl, alkynyl or alkoxy; 
     R 2  is cyano, halogen, alkyl, alkoxy or haloalkyl; 
     R 3  is alkyl; haloalkyl; cycloalkyl; or an unsubstituted or substituted mono- to trinuclear aromatic system, 
     comprises reacting an aryl benzyl ether of the general formula II ##STR2## where X, Y, R, R 1 , R 2  and m have the abovementioned meanings, with a carbonyl halide or with a carboxylic anhydride or with a carboxylic sulfonic anhydride in the presence of an acid and in the presence or absence of a diluent.

A process for preparing 4-alkanoylaryl benzyl ethers of the general formula I ##STR3## where R is hydrogen, halogen, cyano; C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy;

X is CH₂, CH--CH₃, CH--CH₂ --CH₃, CH--OCH₃ or N--OCH₃ ;

Y is oxygen, sulfur, direct linkage or nitrogen which can carry a hydrogen atom, a C₁ -C₄ -alkyl group or a C₁ -C₄ -alkoxy group;

m is 0, 1, 2 or 3, it being possible for the R² radicals to be different when m is 2 or 3;

R¹ is hydrogen; C₁ -C₅ -alkyl, C₃ -C₅ -alkenyl, C₃ -C₅ -alkynyl or C₁ -C₄ -alkoxy, it being possible for these groups to carry one or two halogen atoms;

R² is cyano, halogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or C₁ -C₄ -haloalkyl;

R³ is C₁ -C₁₂ -alkyl; C₁ -C₁₂ -haloalkyl; C₃ -C₈ -cycloalkyl; or an unsubstituted or substituted mono- to trinuclear aromatic system which may, besides carbon atoms, contain one to four nitrogen atoms or one to three hetero atoms selected from a group comprising two nitrogen atoms and one oxygen or sulfur atom, it also being possible for the aromatic radicals to carry one to three substituents selected from a group comprising halogen; C₁ -C₄ -alkyl; C₁ -C₄ -alkoxy, in which the ethers of the formula I where R³ --CO is H are reacted with carbonyl halides or carboxylic anhydrides in the presence of an acid. The acids act as catalysts.

Numerous processes for acylating phenyl alkyl ethers have been disclosed. Conventional methods are reviewed in the following references:

1. G. A. OLAH, Friedel-Crafts and related reactions, vol. III, pages 48-51, 180-189, John Wiley and Sons Inc. New York, 1964

2. D. E. PEARSON, C. A. BUEHLER, Synthesis 1972, 533-542.

These processes are not suitable for acylating aryl benzyl ethers of the formula II because there is preferential cleavage of the benzyl ether under the reaction conditions. This is described in Houben-Weyl, Methoden der organischen Chemie, vol. 6/3, page 146 Table 13 and page 151 lines 24 et seq., Georg Thieme Verlag, Stuttgart 1965. It has also emerged from our own comparative experiments.

The acylated aryl benzyl ethers are obtained only in very low yield by known processes. In the case of the starting materials of the formula II there must also be expected to be yield-reducing side reactions owing to the presence of the R¹ --Y--CO--CX-- functional groups.

It is an object of the present invention to improve the accessibility of the compounds I.

We have found that this object is achieved by a novel process for preparing 4-alkanoylaryl benzyl ethers and 4-aroylaryl benzyl ethers of the formula I which provides surprisingly high yields and which comprises acylating aryl benzyl ethers of the formula II under the reaction conditions described hereinafter; ##STR4##

When carbonyl halides are used as acylating agents in stoichiometric amount based on the compound of the formula II or in an excess of up to 10 mole equivalents above the stoichiometric amount, examples of the catalysts used are Lewis acids, eg. AlBr₃, ZnBr₂, SnCl₄, FeCl₃, FeBr₃, GaCl₃, TiCl₄, InCl₃ and BF₃ in amounts of from 1 to 5 mole equivalents of acid based on the compound II. The chosen reaction temperature is, for example, in the range from -80° C. to 25° C., preferably from -50° C. to 0° C.

When carboxylic anhydrides or carboxylic sulfonic anhydrides are used in stoichiometric amount based on the compound of the formula II or in an excess of up to 30 mole equivalents above the stoichiometric amount, examples of catalysts used are Lewis or Bronsted acids in amounts of from 1 to 5 mole equivalents of acid based on the compound II. The chosen reaction temperature is, for example, in the range from 0° C. to 140° C., preferably from 20° C. to 80° C.

Examples of suitable diluents are inert hydrocarbons such as pentane, hexane, heptane, octane or chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene or dipolar aprotic solvents such as acetonitrile, nitromethane, nitrobenzene or alkyl esters of alkanoic and arylcarboxylic acids such as methyl acetate, ethyl acetate, propyl acetate, methyl benzoate or ethyl benzoate.

The aryl benzyl ethers II used as starting materials are known, and their preparation is described (cf. EP 178 826, EP 253 213, EP 254 426, EP 280 185, EP 336 211, EP 348 766, EP 498 188, EP 398 692 and EP 493 711).

The preparation process according to the invention can be used successfully to synthesize the compounds I according to the definition, in particular for preparing those compounds in which the variables have the following meanings:

R is hydrogen, halogen such as fluorine, chlorine, bromine and iodine, in particular fluorine and chlorine; cyano; C₁ -C₄ -alkyl such as methyl, ethyl, isopropyl and n-propyl, especially methyl and ethyl; C₁ -C₄ -alkoxy such as methoxy, ethoxy, 1-methylethoxy and n-propoxy, in particular methoxy and ethoxy;

X is CH₂, CH--CH₃, CH--CH₂ CH₃, CH--OCH₃ and N--OCH₃ ;

Y is oxygen, sulfur, a direct linkage or nitrogen which can carry a hydrogen atom, a C₁ -C₄ -alkyl group as specified above in general and in particular, or a C₁ -C₄ -alkoxy group as specified above in general and in particular;

m is 0, 1, 2 or 3, it being possible for the R² radicals to be different when m is 2 or 3;

R¹ is hydrogen; C₁ -C₅ -alkyl, especially C₁ -C₄ -alkyl as specified above in general and in particular; C₃ -C₅ -alkenyl such as 1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 3-methyl-2-butenyl, especially 2-propenyl, 2-butenyl and 3-methyl-2-butenyl; C₃ -C₅ -alkynyl such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methyl-2-propynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, especially 2-propynyl and 2-butynyl, C₁ -C₄ -alkoxy such as methoxy, ethoxy, 1-propoxy, 2-propoxy, 2-methyl-1-propoxy; 2-methyl-2-propoxy, 1-butoxy and 2-butoxy,

it being possible for these hydrocarbon groups to carry one or two halogen atoms such as fluorine, chlorine, bromine and iodine, in particular fluorine and chlorine;

R¹ is additionally vinyl or ethynyl, if Y is a direct linkage;

R² is cyano; halogen as specified above in general and in particular; C₁ -C₄ -alkyl as specified above in general and in particular; C₁ -C₄ -alkoxy as specified above in general and in particular; C₁ -C₄ -haloalkyl, especially C₁ -C₂ -haloalkyl such as chloromethyl, dichloromethyl, trichloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, especially trifluoromethyl;

R³ is C₁ -C₁₂ -alkyl, especially C₁ -C₇ -alkyl such as methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, heptyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropoxy, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl;

C₁ -C₁₂ -haloalkyl, especially C₁ -C₇ -haloalkyl such as chloromethyl, bromomethyl, fluoromethyl, trichloromethyl, trifluoromethyl, difluoromethyl, 2-chloroethyl, 2-bromoethyl, 2-fluoromethyl, 2,2,2-trichloroethyl, 3-chloropropyl, 3-bromopropyl, 4-chlorobutyl, 4-bromobutyl, 1-chloroethyl, 1-bromoethyl, 1-fluoroethyl, 5-chloropentyl, 5-bromopentyl, 6-chlorohexyl, 6-bromohexyl, 7-chloroheptyl and 7-bromoheptyl;

C₃ -C₈ -cycloalkyl, especially C₃ -C₆ -cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl;

an unsubstituted or substituted mono- to trinuclear aromatic system which may, besides carbon atoms, contain one to four nitrogen atoms or one or two nitrogen atoms and one oxygen or sulfur atom, especially phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 9-fluorenyl and 2-fluorenyl, in particular phenyl, five-membered heteroaromatic rings containing one to three hetero atoms selected from a group comprising three nitrogen atoms and one oxygen or sulfur atom, such as 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 1-imidazolyl, 2-imidazolyl, 4-imidazolyl, 1,2,4-oxadiazol-3-yl, 1,2,4-oxadiazol-5-yl, 1,2,4-thiadiazol-3-yl, 1,2,4-thiadiazol-5-yl, 1,2,4-triazol-3-yl, 1,3,4-triazol-2-yl, 1,3,4-oxadiazol-2-yl, 1,3,4-thiadiazol-2-yl, 1,3,4-triazol-2-yl, 1,2,3-oxadiazol-4-yl, 1,2,3-oxadiazol-5-yl, 1,2,5-triazol-3-yl, 1,2,3-triazol-4-yl, 1,2,3-triazol-5-yl, 1,2,3-triazol-4-yl, 5-tetrazolyl, 1,2,3,4-thiatriazol-5-yl and 1,2,3,4-oxatriazol-5-yl, in particular 3-pyrrolyl, 3-isoxazolyl, 5-isoxazolyl, 4-oxazolyl, 4-thiazolyl, 4-pyrazolyl, 5-pyrazolyl, 1,3,4-oxadiazol-2-yl and 1,3,4-thiadiazol-2-yl, six-membered heteroaromatic rings containing one to four nitrogen atoms as hetero atoms such as 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 2-pyrazinyl, 1,3,5-triazin-2-yl, 1,2,4-triazin-3-yl and 1,2,4,5-tetrazin-3-yl, in particular 2-pyridinyl, 3-pyridinyl, 2-pyrimidinyl, 4-pyrimidinyl and 1,3,5-triazin-2-yl,

it being possible for these groups to carry one to three halogen atoms such as chlorine, fluorine, bromine and iodine, in particular chlorine and fluorine, and/or one to three C₁ -C₄ -alkyl radicals as specified above in general and in particular, and/or one to three C₁ -C₄ -alkoxy radicals as specified above in general and in particular.

The ketones of the general formula I are valuable intermediates for synthesizing E- and Z-oxime ethers of the general formula III which are used as pesticides, in particular as fungicides, for protecting crops (cf. DE 3937 457, EP 513 580, EP 498 188) ##STR5## where R⁵ is C₁ -C₆ -alkyl, C₂ -C₆ -alkenyl and C₂ -C₆ -alkynyl, it being possible for these radicals to carry one to three halogen atoms and/or one to three of the following radicals:

cyano; nitro; C₁ -C₆ -alkoxy, C₁ -C₆ -alkylthio and C₃ -C₆ -cycloalkyl; R⁵ is additionally a 5- or 6-membered aromatic system, preferably phenyl, which in turn can carry one to three substituents selected from a group comprising halogen, cyano, nitro, C₁ -C₄ -alkyl and C₁ -C₄ -alkoxy.

The final products III can be prepared by conventional processes and methods starting from the ketones of the formula I (cf. DE 39 37 457, EP 513 580, EP 498 188).

Comparative Experiments ##STR6## 9.21 g (50 mmol) of benzyl phenyl ether A and 10.21 g (100 mmol) of acetic anhydride (Ac₂ O) are added dropwise to a solution of 2.43 g (15 mmol) of FeCl₃ in 50 ml ethyl acetate while stirring at 65° C. After 1 h, the mixture is analyzed by gas chromatography (GC). Result: unselective reaction, 80% of the benzyl phenyl ether consumed but the reaction mixture contains less than 1% of compound B. ##STR7## 4 g (30 mmol) of AlCl₃ are introduced into 25 ml of CH₂ Cl₂ at -25° C. while stirring. At -25° C., 2.40 g (30 mmol) of acetyl chloride (AcCl) are added dropwise. After 15 min, 5.53 g (30 mmol) of benzyl phenyl ether A in 10 ml of CH₂ Cl₂ are added dropwise.

After 1 h, the mixture is hydrolyzed and analyzed by GC. Result: completely unselective reaction. 83% benzyl phenyl ether A consumed but the reaction mixture contains less than 1% compound B.

General method for the acylation according to the invention with AlCl₃ ##STR8## 75 mmol of AlCl₃ are introduced into 75 ml of CH₂ Cl₂ at -15° C. 75 mmol of acid chloride 2 are added dropwise at -15° C. over the course of 15 min. The mixture is cooled to -20° to -25° C. and a solution of 30 mmol of aryl benzyl ether II in 20 ml of CH₂ Cl₂ is added dropwise. The mixture is then stirred for 1 h and hydrolyzed on 200 g of ice, 150 ml of CH₂ Cl₂ are added, and the phases are separated. Drying over Na₂ SO₄ is followed by concentration under reduced pressure and recrystallization of the residue. Compound I is obtained.

The following results were obtained by the method described above.

    __________________________________________________________________________                               Solvent     Yield of Compound I                      X    R.sup.2.sub.m                                                                        R.sup.3   Y-R.sup.1                                                                           for crystallizations                                                                       based on Compound                        __________________________________________________________________________                                           II                                       NOCH.sub.3                                                                          2-CH.sub.3                                                                           CH.sub.3  OCH.sub.3                                                                           toluene/heptane = 1/1,                                                                     85%                                      NOCH.sub.3                                                                          2-CH.sub.3                                                                           C.sub.2 H.sub.5                                                                          OCH.sub.3                                                                           toluene/heptane = 1/2                                                                      82%                                      NOCH.sub.3                                                                          2-CH.sub.3                                                                           ClCH.sub.2 CH.sub.2                                                                      OCH.sub.3                                                                           CH.sub.3 OH 58%                                      NOCH.sub.3                                                                          2-CH.sub.3                                                                           ClCH.sub.2 CH.sub.2 CH.sub.2                                                             OCH.sub.3                                                                           CH.sub.3 OH 65%                                      NOCH.sub.3                                                                          2-CH.sub.3                                                                           ClCH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2                                                    OCH.sub.3                                                                           CH.sub.3 OH 70%                                      NOCH.sub.3                                                                          2-CH.sub.3                                                                           Ph        OCH.sub.3                                                                           toluene/heptane = 1/2.5                                                                    81%                                      NOCH.sub.3                                                                          2,5-(CH.sub.3).sub.2                                                                 CH.sub.3  OCH.sub.3                                                                           toluene/heptane = 1/2                                                                      83%                                      NOCH.sub.3                                                                          2-CH.sub.3                                                                           CH.sub.3  NHCH.sub.3                                                                          toluene/heptane = 1/2                                                                      91%                                      __________________________________________________________________________

Catalytic acylation with FeCl₃ ##STR9## 490 mg (3 mmol) of FeCl₃ are introduced into 10 ml of ethyl acetate at 65° C. A mixture of 3.13 g (10 mmol) of aryl benzyl ether 3 and 2.04 g (20 mmol) of Ac₂ O in 10 ml of ethyl acetate is added dropwise. After 16 h at 65° C., the mixture is concentrated under reduced pressure and the residue is chromatographed on silica gel. 2.42 g of compound 4 are obtained in 68% yield.

The compounds specified in the following tables are obtained in a corresponding way.

                                      TABLE                                        __________________________________________________________________________      ##STR10##                                     I                                                                 Physic. data                                                                   [IR (cm.sup.-1);                             Comp.                             NMR (ppm)                                    No. R.sup.3    R.sup.1Y                                                                             X      R.sup.2.sub.m                                                                        mp (°C.)]                             __________________________________________________________________________     1   CH.sub.3   OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           120-122° C.                           2   CH.sub.2 CH.sub.3                                                                         OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           106-108° C.                           3   CH.sub.3   OCH.sub.3                                                                            CHCH.sub.3                                                                            2-CH.sub.3                                                                           96-98° C.                             4   CH.sub.3   NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3                                                                           115-116° C.                           5   cyclopropyl                                                                               NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3                                                                           7.9-6.8(m, 7H),                                                                6.78(m, 1H), 5.0(S, 2H), 3.95                                                  (S, 3H), 2.9(d, 3H), 2.6(m, 1H),                                               2.2(S, 3H), 1.2-0.82(m, 4H)                  6   CH.sub.2 CH.sub.2 Cl                                                                      OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           121-122° C.                           7   CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                             OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           103-104° C.                           8   CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                    OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           108-109° C.                           9   phenyl     OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           141-143° C.                           10  CH.sub.3   OCH.sub.3                                                                            NOCH.sub.3                                                                            2,5-(CH.sub.3).sub.2                                                                 112-114° C.                           11  CH.sub.3   NHCH.sub.3                                                                           NOCH.sub.3                                                                            2,5-(CH.sub.3).sub.2                                                                 143-145° C.                           12  CH.sub.3   OCH.sub.3                                                                            CHCH.sub.3                                                                            2,5-(CH.sub.3).sub.2                                                                 62-64° C.                             13  CH.sub.3   OCH.sub.3                                                                            CHCH.sub.2 CH.sub.3                                                                   2,5-(CH.sub.3).sub.2                                                                 1716, 1672,                                                                    1258, 1140, 1050                             14  CH.sub.3   OCH.sub.3                                                                            NOCH.sub.3                                                                            2-Cl  119-121° C.                           15  CH.sub.3   NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-Cl  124-126° C.                           16  CH.sub.2 CH.sub.2 CH.sub.3                                                                OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           102-105° C.                           17  CH(CH.sub.3).sub.2                                                                        OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3                                                                           105-107° C.                           18  CH.sub.2 CH.sub.3                                                                         OCH.sub.3                                                                            NOCH.sub.3                                                                            2,5-(CH.sub.3).sub.2                                                                 87-89° C.                             19  phenyl     NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3                                                                           1670, 1650, 1599,                                                              1500, 1269, 1119,                                                              1035, 976                                    20  CH.sub.2 CH.sub.3                                                                         OCH.sub.3                                                                            CHCH.sub.3                                                                            2-CH.sub.3                                                                           7.8-7.05(m, 8H), 6.8                                                           (d, 1H), 5.0(s, 2H), 3.9                                                       (s, 3H), 2.9(q, 2H), 2.3                                                       (s, 3H), 1.7(d, 3H),                                                           1.1(t, 3H)                                   21  CH(CH.sub.3).sub.2                                                                        OCH.sub.3                                                                            CHCH.sub.3                                                                            2-CH.sub.3                                                                           1716, 1599, 1251, 1131                       22  CH.sub.2 CH.sub.3                                                                         OCH.sub.3                                                                            CHCH.sub.2 CH.sub.3                                                                   2-CH.sub.3                                                                           70-74° C.                             23  CH.sub.2 CH.sub.3                                                                         NHCH.sub.3                                                                           CHCH.sub.3                                                                            2-CH.sub.3                                                                           1672, 1600, 1253, 1234                       24  CH.sub.3   NHCH.sub.3                                                                           CHCH.sub.3                                                                            2,5(CH.sub.3).sub.2                                                                  1664, 1260, 1143                             25  CH.sub.2 CH.sub.3                                                                         OCH.sub.3                                                                            CHCH.sub.3                                                                            2,5-(CH.sub.3).sub.2                                                                 66-67° C.                             26  CH.sub.2 CH.sub.3                                                                         NHCH.sub.3                                                                           NOCH.sub.3                                                                            2,5-(CH.sub.3).sub.2                                                                 121-123° C.                           27  CH.sub.3   OCH.sub.3                                                                            CHCH.sub.3                                                                            2-Cl  1717, 1674, 1278, 1247                       28  CH.sub.3   OCH.sub.3                                                                            NOCH.sub.3                                                                            2-CH.sub.3 -5-Cl                                                                     1739, 1597, 1251, 1068,                                                        1008                                         29  CH.sub.3   OCH.sub.3                                                                            CHCH.sub.3                                                                            2-CH.sub.3 -5-Cl                                                                     1716, 1598, 1255, 1174                       30  CH.sub.3   NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3 -5-Cl                                                                     1667, 1598, 1254, 1037,                                                        987                                          31  CH.sub.2 CH(CH.sub.3).sub.2                                                               NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3                                                                           6.7-7.8(m, 8H), 5.05                                                           (s, 2H), 3.9(s, 3H), 2.9                                                       (d, 3H), 2.3(s, 3H) and                                                        1.0(d, 6H)                                   32  C(CH.sub.3).sub.3                                                                         NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3                                                                           1665, 1600, 1528, 1255,                                                        1129, 1037                                   33  cyclopentyl                                                                               NHCH.sub.3                                                                           NOCH.sub.3                                                                            2-CH.sub.3                                                                           7.8-6.7(m, 8H), 5.05                                                           (s, 2H), 3.95(s, 3H),                                                          2.9(d, 3H), 2.3(s, 3H),                                                        1.9-1.6(m, 9H)                               34  CH.sub.3   NHCH.sub.3                                                                           NOCH.sub.3                                                                            2,3,5-(CH.sub.3).sub.3                                                               126° C.                               __________________________________________________________________________

Table 1

Compounds of the formula I.1 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A ##STR11## Table 2

Compounds of the formula I.2 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 3

Compounds of the formula I.2 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A. ##STR12## Table 4

Compounds of the formula I.2 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 5

Compounds of the formula I.3 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A. ##STR13## Table 6

Compounds of the formula I.3 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 7

Compounds of the formula I.4 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A. ##STR14## Table 8

Compounds of the formula I.4 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 9

Compounds of the formula I.5 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A. ##STR15## Table 10

Compounds of the formula I.5 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 11

Compounds of the formula I.6 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A. ##STR16## Table 12

Compounds of the formula I.6 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 13

Compounds of the formula I.7 where Y--R¹ is methoxy and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A. ##STR17## Table 14

Compounds of the formula I.7 where Y--R¹ is methylamino and the combination of the substituents R³ and X for a compound in each case corresponds to one line of one column in Table A.

Table 15

Compounds of the formula I.1 where X is NOCH₃ and the combination of the substituents YR¹ and R³ for a compound in each case corresponds to one line of one column In Table B.

Table 16

Compounds of the formula I.2 where X is NOCH₃ and the combination of the substituents YR¹ and R³ for a compound in each case corresponds to one line of one column in Table B.

Table 17

Compounds of the formula I.3 where X is NOCH₃ and the combination of the substituents YR¹ and R³ for a compound in each case corresponds to one line of one column in Table B.

Table 18

Compounds of the formula I.4 where X is NOCH₃ and the combination of the substituents YR¹ and R³ for a compound in each case corresponds to one line of one column in Table B.

Table 19

Compounds of the formula I.5 where X is NOCH₃ and the combination of the substituents YR¹ and R³ for a compound in each case corresponds to one line of one column in Table B.

Table 20

Compounds of the formula I.6 where X is NOCH₃ and the combination of the substituents YR¹ and R³ for a compound in each case corresponds to one line of one column in Table B.

Table 21

Compounds of the formula I.7 where X is NOCH₃ and the combination of the substituents YR.sup. 1 and R³ for a compound in each case corresponds to one line of one column in Table B.

                  TABLE A                                                          ______________________________________                                         R.sup.3              X                                                         ______________________________________                                         CH.sub.3             CHOCH.sub.3                                               CH.sub.3             NOCH.sub.3                                                CH.sub.3 CH.sub.2    CHOCH.sub.3                                               CH.sub.3 CH.sub.2    NOCH.sub.3                                                CH.sub.3 CH.sub.2 CH.sub.2                                                                          CHOCH.sub.3                                               CH.sub.3 CH.sub.2 CH.sub.2                                                                          NOCH.sub.3                                                CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 CHOCH.sub.3                                               CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 NOCH.sub.3                                                CH.sub.3 (CH.sub.2).sub.4                                                                           CHOCH.sub.3                                               CH.sub.3 (CH.sub.2).sub.4                                                                           NOCH.sub.3                                                CH.sub.3 (CH.sub.2).sub.5                                                                           CHOCH.sub.3                                               CH.sub.3 (CH.sub.2).sub.5                                                                           NOCH.sub.3                                                CH.sub.2 --Cl        CHOCH.sub.3                                               CH.sub.2 --Cl        NOCH.sub.3                                                CH.sub.2 Br          CHOCH.sub.3                                               CH.sub.2 Br          NOCH.sub.3                                                CH.sub.2 CH.sub.2 Cl CHOCH.sub.3                                               CH.sub.2 CH.sub.2 Cl NOCH.sub.3                                                CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       CHOCH.sub.3                                               CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       NOCH.sub.3                                                CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      CHOCH.sub.3                                               CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      NOCH.sub.3                                                CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      CHOCH.sub.3                                               CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      NOCH.sub.3                                                CF.sub.3             CHOCH.sub.3                                               CF.sub.3             NOCH.sub. 3                                               CF.sub.2 --CF.sub.3  CHOCH.sub.3                                               CF.sub.2 --CF.sub.3  NOCH.sub.3                                                CH.sub.2 CH.sub.2 Br CHOCH.sub.3                                               CH.sub.2 CH.sub.2 Br NOCH.sub.3                                                CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       CHOCH.sub.3                                               CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       NOCH.sub.3                                                CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      CHOCH.sub.3                                               CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      NOCH.sub.3                                                CH.sub.2 CF.sub.3    CHOCH.sub.3                                               CH.sub.2 CF.sub.3    NOCH.sub.3                                                CH.sub.2 --CH(CH.sub.3).sub.2                                                                       CHOCH.sub.3                                               CH.sub.2 --CH(CH.sub.3).sub.2                                                                       NOCH.sub.3                                                CH.sub.2 --C(CH.sub.3).sub.3                                                                        CHOCH.sub.3                                               CH.sub.2 --C(CH.sub.3).sub.3                                                                        NOCH.sub.3                                                CH(CH.sub.3).sub.2   CHOCH.sub.3                                               CH(CH.sub.3).sub.2   NOCH.sub.3                                                t-Butyl              CHOCH.sub.3                                               t-Butyl              NOCH.sub.3                                                Phenyl               CHOCH.sub.3                                               Phenyl               NOCH.sub.3                                                2-Pyridinyl          CHOCH.sub.3                                               2-Pyridinyl          NOCH.sub.3                                                3-Pyridinyl          CHOCH.sub.3                                               3-Pyridinyl          NOCH.sub.3                                                4-Pyridinyl          CHOCH.sub.3                                               4-Pyridinyl          NOCH.sub.3                                                Cyclopropyl          CHOCH.sub.3                                               Cyclopropyl          NOCH.sub.3                                                Cyclopentyl          CHOCH.sub.3                                               Cyclopentyl          NOCH.sub.3                                                Cyclohexyl           CHOCH.sub.3                                               Cyclohexyl           NOCH.sub.3                                                CH.sub.3             CHCH.sub.3                                                CH.sub.3 CH.sub.2    CHCH.sub.2 CH.sub.3                                       CH.sub.3 CH.sub.2    CHCH.sub.3                                                CH.sub.3 CH.sub.2    CHCH.sub.2 CH.sub. 3                                      CH.sub.3 CH.sub.2 CH.sub.2                                                                          CHCH.sub.3                                                CH.sub.3 CH.sub.2 CH.sub.2                                                                          CHCH.sub.2 CH.sub.3                                       CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 CHCH.sub.3                                                CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 CHCH.sub.2 CH.sub.3                                       CH.sub.3 (CH.sub.2).sub.4                                                                           CHCH.sub.3                                                CH.sub.3 (CH.sub.2).sub.4                                                                           CHCH.sub.2 CH.sub.3                                       CH.sub.3 (CH.sub.2).sub.5                                                                           CHCH.sub.3                                                CH.sub.3 (CH.sub.2).sub.5                                                                           CHCH.sub.2 CH.sub.3                                       CH.sub.2 --Cl        CHCH.sub.3                                                CH.sub.2 --Cl        CHCH.sub.2 CH.sub.3                                       CH.sub.2 Br          CHCH.sub.3                                                CH.sub.2 Br          CHCH.sub.2 CH.sub.3                                       CH.sub.2 CH.sub.2 Cl CHCH.sub.3                                                CH.sub.2 CH.sub.2 Cl CHCH.sub.2 CH.sub.3                                       CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       CHCH.sub.3                                                CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       CHCH.sub.2 CH.sub.3                                       CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      CHCH.sub.3                                                CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      CHCH.sub.2 CH.sub.3                                       CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      CHCH.sub.3                                                CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      CHCH.sub.2 CH.sub.3                                       CF.sub.3             CHCH.sub.3                                                CF.sub.3             CHCH.sub.2 CH.sub.3                                       CF.sub.2 --CF.sub.3  CHCH.sub.3                                                CF.sub.2 --CF.sub.3  CHCH.sub.2 CH.sub.3                                       CH.sub.2 CH.sub.2 Br CHCH.sub.3                                                CH.sub.2 CH.sub.2 Br CHCH.sub.2 CH.sub.3                                       CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       CHCH.sub.3                                                CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       CHCH.sub.2 CH.sub.3                                       CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      CHCH.sub.3                                                CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      CHCH.sub.2 CH.sub.3                                       CH.sub.2 CF.sub.3    CHCH.sub.3                                                CH.sub.2 CF.sub.3    CHCH.sub.2 CH.sub.3                                       CH.sub.2 --CH(CH.sub.3).sub.2                                                                       CHCH.sub.3                                                CH.sub.2 --CH(CH.sub.3).sub.2                                                                       CHCH.sub.2 CH.sub.3                                       CH.sub.2 --C(CH.sub.3).sub.3                                                                        CHCH.sub.3                                                CH.sub.2 --C(CH.sub.3).sub.3                                                                        CHCH.sub.2 CH.sub.3                                       CH(CH.sub.3).sub.2   CHCH.sub.3                                                CH(CH.sub.3).sub.2   CHCH.sub.2 CH.sub.3                                       t-Butyl              CHCH.sub.3                                                t-Butyl              CHCH.sub.2 CH.sub.3                                       Phenyl               CHCH.sub.3                                                Phenyl               CHCH.sub.2 CH.sub.3                                       2-Pyridinyl          CHCH.sub.3                                                2-Pyridinyl          CHCH.sub.2 CH.sub.3                                       3-Pyridinyl          CHCH.sub.3                                                3-Pyridinyl          CHCH.sub.2 CH.sub.3                                       4-Pyridinyl          CHCH.sub.3                                                4-Pyridinyl          CHCH.sub.2 CH.sub.3                                       Cyclopropyl          CHCH.sub.3                                                Cyclopropyl          CHCH.sub.2 CH.sub.3                                       Cyclopentyl          CHCH.sub.3                                                Cyclopentyl          CHCH.sub.2 CH.sub.3                                       Cyclohexyl           CHCH.sub.3                                                Cyclohexyl           CHCH.sub.2 CH.sub.3                                       ______________________________________                                    

                  TABLE B                                                          ______________________________________                                         R.sup.3              Y--R.sup.1                                                ______________________________________                                         CH.sub.3             NH--CH.sub.3                                              CH.sub.3             N(CH.sub.3).sub.2                                         CH.sub.3 CH.sub.2    NH--CH.sub.3                                              CH.sub.3 CH.sub.2    N(CH.sub.3).sub.2                                         CH.sub.3 CH.sub.2 CH.sub.2                                                                          NH--CH.sub.3                                              CH.sub.3 CH.sub.2 CH.sub.2                                                                          N(CH.sub.3).sub.2                                         CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 NH--CH.sub.3                                              CH.sub.3 (CH.sub.2).sub.4                                                                           NH--CH.sub.3                                              CH.sub.3 (CH.sub.2).sub.4                                                                           N(CH.sub.3).sub.2                                         CH.sub.3 (CH.sub.2).sub.5                                                                           NH--CH.sub.3                                              CH.sub.3 (CH.sub.2).sub.5                                                                           N(CH.sub.3).sub.2                                         CH.sub.2 --Cl        NH--CH.sub.3                                              CH.sub.2 --Cl        N(CH.sub.3).sub.2                                         CH.sub.2 Br          NH--CH.sub.3                                              CH.sub.2 Br          N(CH.sub.3).sub.2                                         CH.sub.2 CH.sub.2 Cl NH--CH.sub.3                                              CH.sub.2 CH.sub.2 Cl N(CH.sub.3).sub.2                                         CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       NH--CH.sub.3                                              CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       N(CH.sub.3).sub.2                                         CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      NH--CH.sub.3                                              CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      N(CH.sub.3).sub.2                                         CH.sub.2 (CH.sub.2 ).sub.4 --Cl                                                                     NH--CH.sub.3                                              CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      N(CH.sub.3).sub.2                                         CF.sub.3             NH--CH.sub.3                                              CF.sub.3             N(CH.sub.3).sub.2                                         CF.sub.2 --CF.sub.3  NH--CH.sub.3                                              CF.sub.2 --CF.sub.3  N(CH.sub.3).sub.2                                         CH.sub.2 CH.sub.2 Br NH--CH.sub.3                                              CH.sub.2 CH.sub.2 Br N(CH.sub.3).sub.2                                         CH.sub.2 CH.sub.2 Br N(CH.sub.3).sub.2                                         CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       NH--CH.sub.3                                              CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       N(CH.sub.3).sub.2                                         CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      NH--CH.sub.3                                              CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      N(CH.sub.3).sub.2                                         CH.sub.2 CF.sub.3    NH--CH.sub.3                                              CH.sub.2 CF.sub.3    N(CH.sub.3).sub.2                                         CH.sub.2 --CH(CH.sub.3).sub.2                                                                       NH--CH.sub.3                                              CH.sub.2 --CH(CH.sub.3).sub.2                                                                       N(CH.sub.3).sub.2                                         CH.sub.2 --C(CH.sub.3).sub.3                                                                        NH--CH.sub.3                                              CH.sub.2 --C(CH.sub.3).sub.3                                                                        N(CH.sub.3).sub.2                                         CH(CH.sub.3).sub.2   NH--CH.sub.3                                              CH(CH.sub.3).sub.2   N(CH.sub.3).sub.2                                         t-Butyl              NH--CH.sub.3                                              t-Butyl              N(CH.sub.3).sub.2                                         Phenyl               NH-- CH.sub.3                                             Phenyl               N(CH.sub.3).sub.2                                         2-Pyridinyl          NH--CH.sub.3                                              2-Pyridinyl          N(CH.sub.3).sub.2                                         3-Pyridinyl          NH--CH.sub.3                                              3-Pyridinyl          N(CH.sub.3).sub.2                                         4-Pyridinyl          NH--CH.sub.3                                              4-Pyridinyl          N(CH.sub.3).sub.2                                         Cyclopropyl          NH--CH.sub.3                                              Cyclopropyl          N(CH.sub.3).sub.2                                         Cyclopentyl          NH--CH.sub.3                                              Cyclopentyl          N(CH.sub.3).sub.2                                         Cyclohexyl           NH--CH.sub.3                                              Cyclohexyl           N(CH.sub.3).sub.2                                         CH.sub.3             CH.sub.3                                                  CH.sub.3             CH.sub.3 CH.sub.3                                         CH.sub.3 CH.sub.2    CH.sub.3                                                  CH.sub.3 CH.sub.2    CH.sub.2 CH.sub.3                                         CH.sub.3 CH.sub.2    CH.sub.3                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                                          CH.sub.2 CH.sub.3                                         CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 CH.sub.3                                                  CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2                                                                 CH.sub.2 CH.sub.3                                         CH.sub.3 (CH.sub.2).sub.4                                                                           CH.sub.3                                                  CH.sub.3 (CH.sub.2).sub.4                                                                           CH.sub.2 CH.sub.3                                         CH.sub.3 (CH.sub.2).sub.5                                                                           CH.sub.3                                                  CH.sub.3 (CH.sub.2).sub.5                                                                           CH.sub.2 CH.sub.3                                         CH.sub.2 --Cl        CH.sub.3                                                  CH.sub.2 --Cl        CH.sub.2 CH.sub.3                                         CH.sub.2 Br          CH.sub.3                                                  CH.sub.2 Br          CH.sub.2 CH.sub.3                                         CH.sub.2 CH.sub.2 Cl CH.sub.3                                                  CH.sub.2 CH.sub.2 Cl CH.sub.2 CH.sub. 3                                        CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       CH.sub.3                                                  CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                       CH.sub.2 CH.sub.3                                         CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      CH.sub.3                                                  CH.sub.2 (CH.sub.2).sub.3 --Cl                                                                      CH.sub.2 CH.sub.3                                         CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      CH.sub.3                                                  CH.sub.2 (CH.sub.2).sub.4 --Cl                                                                      CH.sub.2 CH.sub.3                                         CF.sub.3             CH.sub.3                                                  CF.sub.3             CH.sub.2 CH.sub.3                                         CF.sub.2 --CF.sub.3  CH.sub.3                                                  CF.sub.2 --CF.sub.3  CH.sub.2 CH.sub.3                                         CH.sub.2 CH.sub.2 Br CH.sub.3                                                  CH.sub.2 CH.sub.2 Br CH.sub.2 CH.sub.3                                         CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       CH.sub.3                                                  CH.sub.2 CH.sub.2 CH.sub.2 Br                                                                       CH.sub.2 CH.sub.3                                         CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      CH.sub.3                                                  CH.sub.2 (CH.sub.2).sub.3 --Br                                                                      CH.sub.2 CH.sub.3                                         CH.sub.2 CF.sub.3    CH.sub.3                                                  CH.sub.2 CF.sub.3    CH.sub.2 CH.sub.3                                         CH.sub.2 --CH(CH.sub.3).sub.2                                                                       CH.sub.3                                                  CH.sub.2 --CH(CH.sub.3).sub.2                                                                       CH.sub.2 CH.sub.3                                         CH.sub.2 --C(CH.sub.3).sub.3                                                                        CH.sub.3                                                  CH.sub.2 --C(CH.sub.3).sub.3                                                                        CH.sub. 2 CH.sub.3                                        CH(CH.sub.3).sub.2   CH.sub.3                                                  CH(CH.sub.3).sub.2   CH.sub.2 CH.sub.3                                         t-Butyl              CH.sub.3                                                  t-Butyl              CH.sub.2 CH.sub.3                                         Phenyl               CH.sub.3                                                  Phenyl               CH.sub.2 CH.sub.3                                         2-Pyridinyl          CH.sub.3                                                  2-Pyridinyl          CH.sub.2 CH.sub.3                                         3-Pyridinyl          CH.sub.3                                                  3-Pyridinyl          CH.sub.2 CH.sub.3                                         4-Pyridinyl          CH.sub.3                                                  4-Pyridinyl          CH.sub.2 CH.sub.3                                         Cyclopropyl          CH.sub.3                                                  Cyclopropyl          CH.sub.2 CH.sub.3                                         Cyclopentyl          CH.sub.3                                                  Cyclopentyl          CH.sub.2 CH.sub.3                                         Cyclohexyl           CH.sub.3                                                  Cyclohexyl           CH.sub.2 CH.sub.3                                         ______________________________________                                     

We claim:
 1. A process for preparing 4-alkanoylaryl benzyl ether of the formula I ##STR18## wherein R is hydrogen, halogen, cyano, C₁ -C₄ -alkyl, or C₁ -C₄ alkoxy;X is CH₂, CH--CH₃, CH--CH₂ --CH₃, CH--OCH₃ OR N--OCH₃ ; Y is oxygen, sulfur, direct linkage or nitrogen which can carry a hydrogen atom, a C₁ -C₄ -alkyl group or a C₁ -C₄ -alkoxy group; m is 0, 1, 2 or 3, it being possible for the R² radicals to be different when m is 2 or 3; R¹ is hydrogen; C₁ -C₅ -alkyl, C₃ -C₅ -alkenyl, C₃ -C₅ -alkynyl or C₁ -C₄ -alkoxy, it being possible for these groups to carry one or two halogen atoms; R² is cyano, halogen, C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or C₁ -C₄ -haloalkyl; R³ is C₁ -C₁₂ -alkyl; C₁ -C₁₂ -haloalkyl; C₃ -C₈ -cycloalkyl; or an unsubstituted or substituted mono- to trinuclear aromatic system which may, besides carbon atoms, contain one to four nitrogen atoms or one to three hetero atoms selected from the group consisting of two nitrogen atoms and one oxygen or the group consisting of two nitrogen atoms and one sulfur atom, it also being possible for the aromatic radicals to carry one to three substituents each the same or different and selected from the groups consisting of halogen, C₁ -C₄ -alkyl, and C₁ -C₄ -alkoxy; which comprises reacting an aryl benzyl ether of the formula II ##STR19## where X, Y, R, R¹, R² and m have the abovementioned meanings, with a carbonyl halide of the formula R³ --CO-halogen or with a carboxylic anhydride of the formula R³ --COO--CO--R³ or with a carboxylic sulfonic anhydride of the formula R³ COO--SO₂ --R⁴ where R³ has the abovementioned meaning, and R⁴ is C₁ -C₄ -alkyl, C₁ -C₄ -haloalkyl or aryl, in the presence of an acid and in the presence or absence of a diluent.
 2. A process as claimed in claim 1, wherein the reaction is carried out at from -80° C. to +140° C.
 3. A process as claimed in claim 1, wherein said acid is a Lewis acid selected from the group consisting of AlCl₃, AlBr₃, ZnCl₂, ZnBr₂, FeCl₃, FeBr₃, TiCl₄, SnCl₄, GaCl₃, InCl₃ and BF₃.
 4. A process as claimed in claim 1, wherein said acid is a Brosted acid selected from the group consisting of trifluoromethanesulfonic acid, methanesulfonic acid, polyphosphoric acid and sulfuric acid.
 5. A process as claimed in claim 1, wherein said acid is an ion exchange resin with sulfo groups.
 6. A process as claimed in claim 1, wherein said acid is an acid zeolites or a sheet zeolite selected from the group consisting of zeolite ZSM, Montomorillonit KSF and Montmorillonit K10.
 7. A process as claimed in claim 3, wherein the Lewis acids are bound in the form of the metal compounds to an inert carrier selected from the group consisting of alumina, silica, active carbon, sheet-silicates and zeolites. 